It sounds condescending of them to omit the exact model names of their hardware in their 'tech specs' section. I, for one, would like to know what exact model of motherboard I would be getting when I choose 'AMD' or 'Intel Advanced' in the 'Platform' section. Same goes for RAM, SSD, etc.
Just wanted to compare their Thelio mini PC to my last PC setup in a NCASE M1* Mini-ITX case and found that their 'tech specs' page (intentionally?) lacking.
*NCASE M1 cases are discontinued, but are widely available secondhand.
On this one you can see they use a Gigabyte X299 Aorus Ultra Gaming Pro.
However, it's common to do replacements, so am exact model is only going to be possible with bespoke systems IME.
Did you try asking, most people only want a specific bundle of features and don't care about the model numbers per se.